Related papers: Internal Shocks and the Blazar Sequence
By fitting high-quality and simultaneous multi-wavelength (MWL) spectral energy distributions (SEDs) at multiple epochs with a one-zone leptonic jet model, we study jet properties of the three famous blazars Mrk 421, 3C 454.3 and 3C 279. In…
A very bright and fast varying gamma-ray flare has been detected from the blazar 3C 279 on June 16, 2015. We have studied the broadband spectral energy distribution of the source during the flaring episode and in the low activity state…
Blazars are among the most powerful extragalactic objects, as a sub-class of active galactic nuclei. They launch relativistic jets and their emitted radiation shows strong variability across the entire electro-magnetic spectrum. The…
The current status of leptonic jet models for gamma-ray blazars is reviewed. Differences between the quasar and BL-Lac subclasses of blazars may be understood in terms of the dominance of different radiation mechanisms in the gamma-ray…
We describe the time-dependent radiation transfer in blazar jets, within the internal shock model. We assume that the central engine, which consists of a black hole and an accretion disk, spews out relativistic shells of plasma with…
In this work, a time-dependent modeling is developed to study the emission properties of blazars in the low state. Motivated by various observations, we speculate and assume that numerous discrete radiation zones throughout the jet of a…
Mildly-relativistic shocks that are embedded in colliding magnetohydrodynamic flows are prime sites for relativistic particle acceleration and production of strongly variable, polarized multi-wavelength emission from relativistic jet…
The recent long look X-ray observations of TeV blazars have revealed many important new features concerning their time variability. In this paper, we suggest a physical interpretation for those features based on the framework of the…
The dissipation of energy flux in blazar jets plays a key role in the acceleration of relativistic particles. Two possibilities are commonly considered for the dissipation processes, magnetic reconnection -- possibly triggered by…
We introduce a new theoretical model to describe the emitting region in a blazar jet. We assume a one-zone leptonic picture, and construct the particle transport equation for a plasma blob experiencing low-energy, monoenergetic particle…
We put forward a scenario where blazars are classified as flat-spectrum radio quasars, BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying combination of Doppler boosted radiation from the jet, emission from…
We have observed 3C~279 in a gamma-ray flaring state in November 2008. We construct quasi-simultaneous spectral energy distributions (SEDs) of the source for the flaring period of 2008 and during a quiescent period in May 2010. Data have…
We present a description of our numerical code BLAZAR. This code calculates spectra and light curves of blazars during outbursts. The code is based on a model in which the non-thermal flares in blazars are produced in thin shells…
The blazar 3C 279 exhibited twin $\gamma$-ray flares of similar intensity in 2013 December and 2014 April. In this work, we present a detailed multi-wavelength analysis of the 2013 December flaring event. Multi-frequency observations reveal…
In this work, we present the results of our multi-band microvariability study of the famous blazar BL Lac. We performed microvariablity observations of the source in the optical VRI bands for 4 nights in the year 2016. We studied the…
We model rapid variability of multifrequency emission from blazars occurring across the electromagnetic spectrum (from radio to gamma-rays). Lower energy emission is produced by the synchrotron mechanism, whereas higher energy emission is…
Blazars can be divided into two sub-classes namely high energy and low energy peaked blazars. In spectral energy distribution, the first synchrotron hump of the former class peaks in UV/X-rays and in IR/optical bands for the latter class.…
Recent works have developed samples of blazars from among the Fermi-LAT unassociated sources via machine learning comparisons with known blazar samples. Continued analysis of these new blazars tests the predictions of the blazar sequence…
Blazars, a subclass of radio-loud active galactic nuclei with relativistic jets aligned close to our line of sight, emit highly variable non-thermal radiation across the electromagnetic spectrum. The physical origin of their emission and…
In our review of the blazar phenomenon, we discuss blazar models, with a focus on the following issues: sub-parsec jets and their environment; energy dissipation and particle acceleration; and radiative processes.